1. Field of the Invention
The present invention relates to a non-volatile semiconductor storage device.
2. Related Background Art
As for non-volatile semiconductor devices represented by flash memories, there are generally automatic word write operation which makes it possible to write data into memory cells with a word taken as the unit, and automatic page write operation which makes it possible to write a plurality of words in order to shorten the write time (see, for example, JPA 2006-172681 (KOKAI)).
As the capacity of the non-volatile semiconductor storage device becomes large in recent years, the number of words which can be written by performing the automatic page write operation once is also increased from 8 words, 16 words or 32 words in the past to 256 words or 512 words in order to shorten the whole write time.
In the automatic page write operation, for example, the 8-word automatic page write operation of a conventional non-volatile semiconductor storage device, 4-page data decoded with a page address is first output from a data buffer and written. If write time of a head page is finished, then an address generation circuit increases the address by +4 to shift the page address to a next data area corresponding to four pages. The next write data is read out from the data buffer, and write operation is performed in the same way.